The answer that apply;
- Movement of galaxies
- Chemical composition of the Sun.
Light and the time it takes to traverse between particular points in the universe is used to calculate the age of distant stars and galaxies. Because of the vast nature of the universe, light takes earth years for it to travel from one galaxy to another. By knowing the speed of light and the amount of time taken for the light to travel from a distant celestial body, and use of geometric calculations, and brightness measurements we can tell in approximation the age of the celestial body. The age can also star can also be determined by their composition. Youg stars are mainly found have lighter elements such as helium. As they age, they have more composition of heavier elements such as iron. This is due to the fusion at the core of the sun that fuses lighter elements to heavier elements.
The answers that apply are;
- radiometric dating of rocks
- fossil evidence
- gradual processes of rock
Radiometric dating means the use of half-life of naturally decaying elements such as carbon-14 to tell the age of a fossil or rock. The gradual formation of rocks such as lithification of sedimentary rock or metamorphosis of rock is also used to calculate the age of the earth by studying the stage in the process in which the rocks are in and extrapolating the age using calculations.
